ROLE AND EXPERIENCE WITH THERMAL MONITORS IN REACTOR VESSEL SURVEILLANCE CAPSULES

摘要

The surveillance capsule irradiation temperature is important to assure that the data obtained are representative of the reactor vessel beltline materials. Capsules evaluated showed that the temperatures exceed 588℉(309°C) during in-reactor exposure. The monitors melt as the result of normal system operating temperature transients up to 588℉(309°C). The apparent melting of thermal monitors at temperatures greater than 588℉(309°C) is the result of long term exposure to temperatures close to the material melting temperature, causing slumping and the appearance of melting.